Pertussis antibodies and vaccination coverage among healthcare professionals in Brazil is inadequate: A cross-sectional serological study

INTRODUCTION

Worldwide, tetanus-diphtheria-acellular pertussis (Tdap) vaccination coverage of healthcare professionals (HCPs) is below 40%, but this data is not available for Brazil. We hypothesize that a high number of HCPs are not immune to pertussis in Brazil. Main objective was to determine the seroprevalence of anti-pertussis toxin (anti-PT IgG) among HCPs. Secondary objectives were to evaluate Tdap vaccination coverage, to assess predictive factors associated with anti-PT IgG, and to estimate the decay of anti-PT IgG and time to Tdap vaccination.

METHODS

Observational cross-sectional serological study in 352 HCPs who worked at São Paulo Hospital - Federal University of São Paulo (UNIFESP) in 2020, approved by UNIFESP Ethics Committee. Data collected included sociodemographics, knowledge about Tdap, and vaccination status. Anti-PT IgG were quantified by ELISA: <10 IU/mL seronegative and ≥ 10-1000 IU/mL seropositive. Titers ≥ 10-50 IU/mL were classified low positivity, indicating no recent B. pertussis infection or Tdap vaccination; >50 IU/mL high positivity, indicating recent B. pertussis infection or Tdap vaccination, and > 100 IU/mL as acute B. pertussis infection or Tdap vaccination in the previous year. Comparisons were done by Chi-square test, multivariable logistic regression, and Pearsońs correlation, at 5% p-level.

RESULTS

331/352 HCPs were not aware the Brazilian National Immunization Program recommends Tdap for all HCPs and pregnant women. 68/339 HCPs received Tdap (mean 3.1 ± 2.0 years). 55/352 were seronegative for pertussis, all unvaccinated. 56/271 with no history of Tdap vaccination had high positivity. The probability of anti-PT IgG > 50 IU/mL was 11.5 times higher in Tdap vaccinated HCPs than in non-vaccinated (p < 0.001). There was a weak but significant correlation between anti-PT IgG and interval of Tdap vaccination (r = 0.404; p = 0.001). Anti-PT IgG dropped 5 IU/mL/year (p = 0.001).

CONCLUSION

Better education of HCPs on needs and benefits of Tdap vaccination is critical. Goals must be to improve HCPs vaccination coverage.

Cell activation, PD-1 expression and in vitro cytokine production in patients with juvenile systemic lupus erythematosus

BACKGROUND

Juvenile systemic lupus erythematosus (jSLE) is known to be more severe and with a higher frequency of renal and central nervous system impairment when compared to systemic lupus erythematosus in adults. The study of immunological characteristics of jSLE patients might help to envisage better treatment strategies to reduce the burden of the disease.

OBJECTIVE

To characterize peripheral lymphocytes, assessing activation markers, and PD-1 expression on T cells; to evaluate in vitro cytokine expression upon stimulation in jSLE patients and age-matched controls.

METHODOLOGY

Eighteen jSLE patients on low disease activity and 25 matched healthy adolescents were evaluated for immune activation and PD-1 expression on peripheral blood lymphocytes by flow cytometry. Twenty-one cytokines were assessed by X-MAP technology after in vitro stimulation of peripheral blood with phytohemagglutinin.

RESULTS

jSLE patients had lower numbers of CD4 T, CD8 T, B, and NK cells; higher central memory CD8 T cell percentages were noted in jSLE adolescents in comparison with controls (p = 0.014). B cells subsets showed a higher percentage of exhausted memory subset than controls (p = 0.014). The expression of PD-1 on CD4 T and CD8 T cells did not show relevant changes in jSLE adolescents. After stimulation of peripheral blood, cell supernatant of jSLE patients showed a trend to lower concentrations of IL-10 (p=0.080) and higher concentrations of IL-23 (p = 0.063) than controls.

CONCLUSIONS

jSLE patients on low disease activity maintain lymphopenia of all subsets, with a B cell profile of exhaustion. Upon in vitro stimulation, peripheral blood cell supernatant showed a shift to IL-23, suggesting a role of inhibitors of this cytokine as another potential therapeutic target for those patients.

Rubella antibodies in vertically and horizontally HIV-infected young adults vaccinated early in life and response to a booster dose in those with seronegative results

BACKGROUND

Very limited data are available on the persistence of rubella antibodies in vertically HIV-infected individuals who were vaccinated early in life.

METHODS

Prospective, cohort study on 4 groups of patients: 96 vertically HIV-1-infected individuals (v-HIV), 69 horizontally HIV-1-infected individuals (h-HIV), 93 healthy controls previously vaccinated for rubella (vac-CON) and 20 healthy controls with history of rubella disease (dis-CON). A blood sample was collected and rubella antibodies were analyzed by ELISA. Rubella antibodies above 10 IU/mL were considered protective. Individuals with seronegative results were offered an extra MMR vaccine dose and were tested at least 30 days afterwards.

RESULTS

Time since previous rubella vaccination was similar in v-HIV, h-HIV and vac-CON (16, 11 and 11 years; p = 0.428). v-HIV and h-HIV were also comparable regarding median CD4 T cells (613 and 614 cells/mm³; p = 0.599) and percentage on ART (93.8% and 98.6%; p = 0.135) at study entry. v-HIV had less individuals on virological suppression (63.5%) compared to 85.5% in h-HIV (p < 0.001). Rubella seropositivity and antibodies were significantly lower in v-HIV compared to h-HIV (32.3% vs 65.5%, 4.3 IU/mL vs 21.1 IU/mL; p < 0.001). Time interval between the last rubella vaccine dose and study entry was associated with an increase of rubella seronegativity, with a 7% higher chance of seronegativity for each one-year increase. After an extra MMR dose, 40 out of 48 (83.3%) seronegative individuals responded, with no significant difference among groups considering rubella seropositivity and antibody levels.

CONCLUSION

As vertically HIV-infected individuals reach adolescence and adulthood, assessment of vaccine antibodies can identify those who might benefit from an extra vaccine dose.

SCID and Other Inborn Errors of Immunity with Low TRECs - the Brazilian Experience

Severe combined immunodeficiency, SCID, is a pediatric emergency that represents the most critical group of inborn errors of immunity (IEI). Affected infants present with early onset life-threatening infections due to absent or non-functional T cells. Without early diagnosis and curative treatment, most die in early infancy. As most affected infants appear healthy at birth, newborn screening (NBS) is essential to identify and treat patients before the onset of symptoms. Here, we report 47 Brazilian patients investigated between 2009 and 2020 for SCID due to either a positive family history and/or clinical impression and low TRECs. Based on clinical presentation, laboratory finding, and genetic information, 24 patients were diagnosed as typical SCID, 14 as leaky SCID, and 6 as Omenn syndrome; 2 patients had non-SCID IEI, and 1 remained undefined. Disease onset median age was 2 months, but at the time of diagnosis and treatment, median ages were 6.5 and 11.5 months, respectively, revealing considerable delay which affected negatively treatment success. While overall survival was 51.1%, only 66.7% (30/45) lived long enough to undergo hematopoietic stem-cell transplantation, which was successful in 70% of cases. Forty-three of 47 (91.5%) patients underwent genetic testing, with a 65.1% success rate. Even though our patients did not come from the NBS programs, the diagnosis of SCID improved in Brazil during the pilot programs, likely due to improved medical education. However, we estimate that at least 80% of SCID cases are still missed. NBS-SCID started to be universally implemented in the city of São Paulo in May 2021, and it is our hope that other cities will follow, leading to early diagnosis and higher survival of SCID patients in Brazil.

Assessment of liver disease by non-invasive methods in perinatally infected Brazilian adolescents and young adults living with Human Immunodeficiency Virus (HIV)

INTRODUCTION

Effective and long-term combined antiretroviral therapy (cART) has decreased morbidity and mortality in HIV-infected individuals. Despite treatment advances, HIV-infected children continue to develop noninfectious conditions, including liver fibrosis.

METHODS

Cross-sectional study designed to identify liver fibrosis in HIV-infected adolescents and young adults, in an outpatients clinic of Pediatric Infectious Diseases Division at Escola Paulista de Medicina/Universidade Federal de São Paulo (UNIFESP), diagnosed by noninvasive methods (liver elastography-FibroScan®, APRI and FIB4). Variables examined included demographics, clinical, laboratories, HIV treatment. All participants underwent FibroScan® to measure liver parenchyma elasticity. Values equal to above 7.0 kPa were interpreted as the presence of significant liver fibrosis. Two different biomarkers of liver fibrosis were employed: the AST-to-Platelet Ratio Index (APRI) and the Fibrosis-4 score (FIB-4). APRI values above 1.5 have been considered as levels of clinically significant liver fibrosis and FIB-4 values above 3.25 suggested the presence of advanced fibrosis.

RESULTS

Between August 2014 and March 2017, the study enrolled 97 patients, age 10-27 years old, fourteen of 97 subjects (14.4%) presented liver stiffness (≥7 kPa) detected by the liver elastography. No patient had APRI> 1.5. No patient had FIB4 value > 3.25. The only isolated laboratory parameter that could be significantly associated with high liver stiffness was thrombocytopenia (p = 0.022, Fisher's exact test).

CONCLUSION

Liver stiffness was identified in 14.4% (14/97) of this cohort by liver elastography. Liver disease in HIV-infected adolescents and young adults manifests itself silently, so should be routinely investigated.

Immune system: development and acquisition of immunological competence

OBJECTIVES

To describe the ontogeny of the immune system and the adaptive mechanisms of the immune system in the neonatal period, with an emphasis on transplacental antibody transport and breastfeeding.

SOURCE OF DATA

Non-systematic literature review in the PubMed database.

SUMMARY OF THE FINDINGS

The last two decades have witnessed a great advance in the knowledge of the immune system since conception. Several investigation tools have provided insight on phenomena that were previously inadequately understood. Still expanding, the functional and molecular investigation of various aspects of the immune system will make it possible to understand how intra-uterus maternal-fetal exchanges, the maternal microbiota interacting with the fetus and newborn, and the acquisition of immunological competence occur in healthy and disease scenarios.

CONCLUSIONS

In-depth knowledge of the development of the immune system and of the adaptive mechanisms that allow a safer transition to the extrauterine environment are fundamental components of optimizing maternal and young infant vaccination, as well as the strategies associated with full postnatal development, and the early diagnosis and treatment of innate errors of immunity.

Tdap booster to adolescents with juvenile idiopathic arthritis on and off anti-TNF agents is safe and immunogenic

INTRODUCTION

The response to vaccines in juvenile idiopathic arthritis (JIA) patients on and off anti-tumor necrosis factor (anti-TNF) agents remains highly discussed. There are no published studies on the immune response following a Tdap booster dose in JIA patients so far.

OBJECTIVE

To evaluate the immune response and safety after a Tdap booster in JIA patients and in healthy adolescents.

METHODS

Nineteen adolescents with JIA according to the ILAR criteria on anti-TNF medication, 19 adolescents with JIA off anti-TNF medication, and 27 healthy adolescents (control group) were compared after a Tdap booster. Adverse events and disease activity were evaluated. Lymphocyte immunophenotyping was performed by flow cytometry. Tetanus, diphtheria and pertussis toxin antibodies were assessed by ELISA; whole blood was stimulated with whole-cell pertussis, and supernatants were assessed for cytokines by xMAP.

RESULTS

The three groups showed a similar frequency of adverse events. There was no disease reactivation after the Tdap booster. Tetanus, diphtheria and pertussis antibodies showed a significant response when D0 and D14 concentrations were compared in both JIA groups and controls. Over time, a different pattern of response to the Tdap booster was observed among the groups for tetanus antibodies (p = 0.005) but not for diphtheria and pertussis antibodies. In contrast to the protection attained for tetanus and diphtheria, in the three groups, not all individuals showed pertussis seroconversion at either D14 or D28. In addition, the seroconversion of three subjects with JIA on anti-TNF medication was not maintained at D28. JIA patients off anti-TNF showed a higher percentage of naive CD8 + T cells (p = 0.007) and central memory CD8 + cells (p = 0.003) and a lower percentage of effector CD8 + T cells (p = 0.003) and NK cell numbers (p = 0.018) than the control group. The JIA group off anti-TNF medication had fewer B lymphocytes than both the JIA group on anti-TNF medication and the control group (p = 0.016). Cellular immunity to Bordetella pertussis showed that IFNγ levels were significantly lower in both JIA groups than in the control group (p = 0.003), IL10 levels were higher in the JIA off anti-TNF group (p = 0.009), IL17A and IL5 levels were lower in the JIA on anti-TNF group than in the control group (p = 0.018 and p = 0.016, respectively); however, an increase in IFNγ (p = 0.008), IL17A (p = 0.030) and TNFα (p = 0.041) levels was observed at D14 in both patient groups. Both JIA groups showed higher levels of IL21 than the control group (p = 0.023).

CONCLUSION

We conclude that individuals with JIA on or off anti-TNF agents showed a good response to a booster dose for the three antigens studied in the absence of major adverse events and without the reactivation of the disease.

Adequate tetanus but poor diphtheria and pertussis response to a Tdap booster in adolescents with juvenile systemic lupus erythematosus

BACKGROUND

Reports on vaccine responses in immunocompromised patients, such as juvenile systemic lupus erythematosus (jSLE), have shown highly variable results.

OBJECTIVE

To compare the immune response and safety after a Tdap booster in 26 jSLE patients and 26 matched healthy adolescents.Methodology: Adverse events and disease activity were evaluated. Lymphocyte immunophenotyping was performed by flow cytometry. Tetanus, diphtheria and pertussis toxin antibodies were assessed by ELISA; whole blood was stimulated with whole cell pertussis and supernatants were assessed for cytokines by xMAP.

RESULTS

Both groups showed a similar frequency of adverse events. There was no evidence of disease reactivation after Tdap booster in the jSLE cohort. Both groups showed a significant increase in antibody titers for all three antigens on D14 and D28 (p < 0.001). jSLE patients had a significantly lower increase in diphtheria titers than the control group (p = 0.007). jSLE patients had a distinct titer increase of tetanus and pertussis antibodies when compared to controls (p = 0.004 and p < 0.001, respectively). There was a lower frequency of pertussis seroconversion in the jSLE group on D14 (p = 0.009), D28 (p = 0.023), D12m (p = 0.015) and D24m (p = 0.004). Cellular immune response to Bordetella pertussis showed significantly lower levels of IFNγ (p < 0.001) and higher levels of IL10, IL12, IL21 and TNFα in jSLE patients than controls.

CONCLUSIONS

jSLE patients had good response to Tdap booster dose for the tetanus antigen, but not for diphtheria and pertussis. This vaccine was safe in relation to adverse events and absence of disease reactivation.

Invasive pneumococcal disease in children with cancer: Incidence density, risk factors and isolated serotypes

Background

Pediatric oncology patients (POP) have a high risk of infections due to impaired immunity. Invasive pneumococcal disease (IPD) is an important cause of severe infection in these patients and it is associated with high mortality. This study aimed to evaluate the incidence and risk factors associated with IPD at a Pediatric Oncology Center in Brazil.

Methods

This was a retrospective case-control study. All IPD cases in children with cancer from 2005 through 2016 were reviewed. Each case of IPD was matched with two controls from a cohort of patients matched for year of IPD, age and disease in order to assess risk factors. The incidence density was calculated as the number of IPD per 100,000 patients-year.

Results

A total of 51 episodes of IPD in 49 patients was identified. All pneumococci were isolated from blood cultures. The median age was five years and 67% were male; mortality rate was 7.8%. The IPD incidence density rate in POP was 311.21 per 100,000 patients-year, significantly higher than the rate in the general pediatric population. Severe neutropenia was the only risk factor associated with IPD, after multivariate conditional logistic regression analysis.

Conclusion

Although pneumococcal disease decreased after the introduction of 10-valent pneumococcal vaccine in the Brazilian national immunization schedule in 2010, there was no decrease in the IPD incidence rate in our cohort. A higher coverage rate of pneumococcal vaccination in children in the general population might be necessary to reduce the incidence rate in this high-risk population.

Candida spp bloodstream infections in a Latin American Pediatric Oncology Reference Center: Epidemiology and associated factors

BACKGROUND

Invasive fungal disease is a significant cause of morbidity and mortality in immunosuppressed children. The recognition of patients at risk for candidaemia is paramount to a better prognosis.

OBJECTIVES

To characterize Candida spp bloodstream infections (BSI) in a reference centre for paediatric oncology and to describe the most prevalent risk factors associated with candida infections.

PATIENTS/METHODS

This is a retrospective cohort study carried out with paediatric patients followed up with at the Institute of Pediatric Oncology, Brazil, who presented positive blood culture for Candida spp from January 2004 to December 2016.

RESULTS

Ninety episodes of candidaemia were analysed; patients had a median age of 4.5 years, and 57.8% were males, with a diagnosis of solid tumours in 54.5% of cases. The most common Candida species were C albicans (35.6%), C parapsilosis (30.0%) and C tropicalis (16.7%). C tropicalis BSI was associated with neutropenia and skin lesions. Therapy was successful in 67.1% of the episodes. Older age and thrombocytopenia were associated with therapeutic failure. Death within 30 days occurred in 24.4% of patients; predictive factors were older age and admission to an ICU C parapsilosis candidaemia was a protective factor for death when compared to C albicans.

CONCLUSION

The main species isolated were C albicans, C parapsilosis and C tropicalis. C tropicalis BSI was associated with neutropenia and skin lesions. The death rate was significant, and a worse prognosis was associated with older age, thrombocytopenia and admission to an ICU C parapsilosis infection proved to be a protective factor against mortality.

Opportunistic infections in pediatrics: when to suspect and how to approach

OBJECTIVES

To describe the characteristics of opportunistic infections in pediatrics regarding their clinical aspects, as well as the diagnostic strategy and treatment.

SOURCE OF DATA

Non-systematic review of literature studies in the PubMed database.

SYNTHESIS OF DATA

Opportunistic infections caused by non-tuberculous mycobacteria, fungi, Herpesvirae, and infections affecting individuals using immunobiological agents are analyzed. Because these are severe diseases with a rapid evolution, diagnostic suspicion should be early, associated with the patient's clinical assessment and history pointing to opportunistic infections. Whenever possible, samples of secretions, blood, and other fluids and tissues should be collected, with early therapy implementation.

CONCLUSIONS

Despite the improved diagnosis of opportunistic infections in recent years, they remain a challenge for pediatricians who are not used to these infections. They should raise the suspicion and start treating the case, but should also resort to specialists in the management of these infections to provide a better outcome for these patients, who still have high mortality.

Low Rates of Poliovirus Antibodies in Primary Immunodeficiency Patients on Regular Intravenous Immunoglobulin Treatment

PURPOSE

Poliovirus has been nearly eliminated as part of a world-wide effort to immunize and contain circulating wild-type polio. Nevertheless, poliovirus has been detected in water supplies and represents a threat to patients with humoral immunodeficiencies where infection can be fatal. To define the risk, we analyzed antibodies to poliovirus 1, 2, and 3 in serum samples collected over a year from patients with primary immunodeficiency diseases (PID) on regular intravenous immunoglobulin (IVIG) replacement.

METHODS

Twenty-one patients on regular IVIG replacement therapy were evaluated: Twelve patients with common variable immune deficiency (CVID), six with X-linked agammaglobulinemia (XLA), and three with hyper IgM syndrome (HIGM). Over 1 year, four blood samples were collected from each of these patients immediately before immunoglobulin infusion. One sample of IVIG administered to each patient in the month before blood collection was also evaluated. Poliovirus antibodies were quantified by seroneutralization assay.

RESULTS

All IVIG samples had detectable antibodies to the three poliovirus serotypes. Despite that, only 52.4, 61.9, and 19.0% of patients showed protective antibody titers for poliovirus 1, 2, and 3, respectively. Only two patients (9.5%) had protective antibodies for the three poliovirus serotypes on all samples. Most patients were therefore susceptible to all three poliovirus serotypes.

CONCLUSIONS

This study demonstrates the need for ongoing vigilance regarding exposure of patients with PID to poliovirus in the community.

Safe administration of rotavirus vaccine in a cohort of infants exposed to immunosuppressive drugs during gestation

In utero exposure to immunosuppressive drugs might be a contraindication to rotavirus vaccine, but that may vary according to the immunosuppressive regimen. We evaluated 24 infants born to kidney transplanted mothers exposed to 3 immunosuppressants during pregnancy (prednisone, azathioprine, and tacrolimus or cyclosporine) and 31 control infants not exposed to these medications. No differences in adverse events were detected after rotavirus vaccination at 2 and 4 months.

Adherence and immune response to revaccination following hematopoietic stem cell transplantation at a pediatric onco-hematology reference center

BACKGROUND

Revaccination after hematopoietic stem cell transplantation (HSCT) is necessary to compensate for the loss of immunological memory. The aims of this study were to evaluate the adherence to revaccination schedule and the humoral immune response to different vaccine antigens in HSCT pediatric and young adult patients.

METHODS

Patients submitted to HSCT for over 3 years were recruited. After written informed consent, a questionnaire was filled in, the vaccination card was analyzed, a blood sample was collected and tested by ELISA for diphtheria, Haemophilus influenzae type b (Hib), hepatitis A, hepatitis B, tetanus, measles, rubella, and varicella antibodies.

RESULTS

Sixty-three patients (mean age at HSCT, 10.7 years) were evaluated. Forty-one (65%) were male; 34 (54%) had allogeneic and 29 (46%), autologous HSCT. Complete adherence to diphtheria revaccination was found in 79.4% patients and seropositivity was found in 92% of those who completed the revaccination schedule; for Hib, 68.3% adherence and 95.3% seropositivity were observed; for hepatitis A, 63.5% adherence and 92.5% seropositivity; for 3 doses of hepatitis B, 86.8% adherence and 79.2% seropositivity; for tetanus, 79.4% adherence and 100% seropositivity; for measles and rubella, 17.5% adherence and 100% seropositivity; for varicella, 7.9% adherence and 100% seropositivity. The existence of a Vaccination Center for Special Immunobiologicals in patients' municipality was positively associated with completed vaccine schedule; on the other hand, chronic GVHD was negatively associated with revaccination adherence.

CONCLUSION

Hematopoietic stem cell transplantation patients showed good seropositivity rates after complete vaccination schedule. However, a low coverage rate was observed for live attenuated antigens.

Humoral immune response to measles and varicella vaccination in former very low birth weight preterm infants

Introduction

Objectives

Methods

Results

Conclusions

Hypogammaglobulinemia in children: a warning sign to look deeply?

This study investigated phenotypic and functional characteristics of lymphocytes in children with common variable immunodeficiency (CVID) and unclassified hypogammaglobulinemia (UH), as well as B-cell subsets in non-consanguineous parents. Blood samples of 30 children, CVID (n = 9), UH (n = 9), healthy donors HD (n = 12), and 19 adults (parents and controls) were labeled by a combination of surface markers to identify CD4, CD8 T-cell and B-cell subpopulations. T-cell cytokine production in children was analyzed in vitro after stimulation with phytohemagglutinin (PHA) and tetanus toxoid. We observed low percentages of switched memory B cells in children with CVID, increase in total CD4⁺ T-cell counts, and high percentages of transitional B cells only in UH group. Analysis of T-cell immunity showed that CVID children had decreased percentages of CD8⁺ IFN-γ-producing cells after stimulation with PHA and tetanus toxoid. Parent of children with CVID had low percentages of naive B cell and increased percentages of memory B cells in comparison with controls. These results suggest that (i) early combined immune defect in children with CVID and (ii) a possible familial B-cell disturbance in pediatric CVID.

Serum anti-phenolic glycolipid-1 IgA correlates to IgM isotype in leprosy patients: a possible candidate for seroepidemiological surveys?

OBJECTIVE

The aim of this study was to compare serum anti-phenolic glycolipid-1 IgA, IgG, and IgM levels in leprosy patients and controls.

METHOD

Analysis of anti-PGL-1 IgA, IgG, or IgM in serum samples from multibacillary (MB, n=32) and paucibacillary (PB, n=22) leprosy patients, and in non-endemic controls (n=17), using an indirect enzyme-linked immunosorbent assay.

RESULTS

A strong correlation between serum IgM and IgA isotypes was found (r=.745, P<.0001) in MB patients. A moderate correlation was found in all analyses in PB patients. A moderate agreement was found between anti-PGL1 IgA and IgM tests. Based on the ROC curves, the cut-off values were selected and the parameters of validation were calculated. Considering the clinical forms altogether, the diagnostic sensitivities were 50.0% for IgA, 22.2% for IgG, and 74.1% for IgM. The positive (VPP) and negative (VPN) predictive values were estimated for each isotype. For IgA, the VPP and VPN were, respectively, 100.0% (87.0%-100.0%; 95% confidence interval) and 38.7% (24.4%-54.5%); for IgG, 100% (87.0%-100.0%) and 28.8% (17.8%-42.1%), respectively; and for IgM, 95.2% (83.8%-99.4%) and 51.7% (32.5%-70.6%), respectively.

CONCLUSION

Despite the limiting factors, anti-PGL1 IgA correlates to IgM levels and it could be considered as a possible laboratorial tool to be also used, for instance, in serological follow-up studies.

Immune development in HIV-exposed uninfected children born to HIV-infected women

Immunological and clinical findings suggestive of some immune dysfunction have been reported among HIV-exposed uninfected (HEU) children and adolescents. Whether these defects are persistent or transitory is still unknown. HEU pediatric population at birth, 12 months, 6-12 years were evaluated in comparison to healthy age-matched HIV-unexposed controls. Plasma levels of LPS, sCD14, cytokines, lymphocyte immunophenotyping and T-cell receptor excision circles (TREC) were assessed. HEU and controls had similar LPS levels, which remained low from birth to 6-12 years; for plasma sCD14, IL-2, IL-6, IL-7, IL-10, IL-12p70, IL-13, IL-17, IFN-γ, TNF-α, G-CSF, GM-CSF and MCP-1, which increased from birth to 12 months and then decreased at 6-12 years; and for TREC/10⁶ PBMC at birth in HEU and controls. By contrast, plasma MIP-1β levels were lower in HEU than in controls (p=0.009) at 12 months, and IL-4 levels were higher in HEU than controls (p=0.04) at 6-12 years. Immune activation was higher in HEU at 12 months and at 6-12 years than controls based on frequencies of CD38+HLA-DR+CD8+T cells (p=0.05) and of CD38+HLA-DR+CD4+T cells (p=0.006). Resting memory and activated mature B cells increased from birth to 6-12 years in both groups. The development of the immune system in vertically HEU individuals is comparable to the general population in most parameters, but subtle or transient differences exist. Their role in influencing clinical incidences in HEU is unknown.

ADHERENCE TO INFLUENZA VACCINATION AMONG MEDICAL STUDENTS DURING AND AFTER INFLUENZA A (H1N1) PANDEMIC

This study evaluated the adherence to influenza vaccination among medical students in 2010 and 2011. From August to December 2011, a questionnaire was used to record the influenza vaccination in 2010 and 2011, reasons for acceptance of the influenza vaccine and knowledge of healthcare workers about the influenza vaccine recommendation. One hundred and forty-four students from the 2ndto the 6th years of the medical school were interviewed. A great adherence to pandemic influenza vaccine was noted in 2010, (91% of the students), with "self-protection" being the most common reason cited for vaccination. Other determinants for the vaccination during pandemic were "convenient access to vaccine" and "encouragement by peers and teachers in workplaces and at the university". However, there was a great decay in the acceptance to vaccine in the next influenza season (2011). Only 42% of the students received the vaccine. They claimed "lack of time" and "have forgotten to take the vaccine" as the main reasons. The "knowledge on the recommendation of influenza vaccine to healthcare workers" increased when the students come to attend the last year of the medical school, but that was an insufficient motivator for vaccination. Strategies to increase vaccination should be based on the abovementioned aspects for the adoption of effective measures in both, pandemic and seasonal periods.

CLINICAL MANAGEMENT OF LOCALIZED BCG ADVERSE EVENTS IN CHILDREN

BCG adverse events (BCG-AE) are rare conditions with no well-established treatment. This study aims to describe clinical characteristics and outcome of localized BCG-AE. Children with BCG-AEs who were treated at the Reference Center for Special Immunobiologicals of the Federal University of São Paulo from 2009 to 2011 were included. Patients were followed monthly until 3 months after healing. One hundred and twenty-seven patients with localized BCG-AE were followed: 67 (52.7%) had suppurative lymphadenitis; 30 (23.6%) injection-site abscess; five (3.9%) had enlarged lymph node > 3 cm; four (3.1%) had ulcer > 1 cm; and one (0.8%) had a local bacterial infection. Five patients (3.9%) had more than one BCG-AE simultaneously. Fifteen patients (11.8%) had atypical manifestations: seven wart-like lesions; five BCG reactivations; two other dermatologic lesions and one with vasomotor phenomenon. Isoniazid was used in 96 patients with typical BCG-AE (85.7%) until lesion resolution which took place 3.1 months later (in median); the healing rate was 90.6%. Patients with atypical manifestations had an individual approach. Regarding the outcome, 105/112 patients with typical AE and 13/15 patients with atypical AE had resolution of BCG-AE. Localized BCG-AE caused by BCG Moreau RJ had positive outcome when treated with a short course of isoniazid. Atypical BCG-AE are not infrequent.

PROTECTIVE LEVELS OF VARICELLA-ZOSTER ANTIBODY DID NOT EFFECTIVELY PREVENT CHICKENPOX IN AN X-LINKED AGAMMAGLOBULINEMIA PATIENT

We describe the case of an eight-year-old boy with X-linked agammaglobulinemia who developed mild varicella despite regular intravenous immunoglobulin (IVIG) therapy. He maintained protective antibody levels against varicella and the previous batches of IVIG that he received had adequate varicella-specific IgG levels. The case illustrates that IVIG may not prevent VZV infection.

Response to immunization in children born to renal transplant recipients using immunosuppressive drugs during gestation

The use of immunosuppressive drugs can impair vaccination responses. When used during pregnancy, they may interfere with the development of the fetus's immune system. However, little is known regarding their influence on infant's response to vaccinations. Twenty-seven children born to renal transplant mothers (Tx) taking immunosuppressive drugs and 31 healthy children had the humoral immune response and reactogenicity to tetanus, Haemophilus influenzae type b (Hib) and 7 pneumococcal serotypes evaluated. The evolution of BCG vaccine scar was also registered. Antibodies were measured by ELISA. Lymphocyte immunophenotyping was performed on cord blood and at 7-8 months of age. Among Tx neonates, 82.4% had low B lymphocyte numbers at birth, and 29.4% had also low numbers of other lymphocyte subpopulations. Nevertheless, all children developed protective antibodies with similar antibody concentrations to the control group. Vaccine reactogenicity was similar in both groups and BCG healing was uneventful.

Incidence of active mycobacterial infections in Brazilian patients with chronic inflammatory arthritis and negative evaluation for latent tuberculosis infection at baseline--a longitudinal analysis after using TNFa blockers

Several studies point to the increased risk of reactivation of latent tuberculosis infection (LTBI) in patients with chronic inflammatory arthritis (CIAs) after using tumour necrosis factor (TNF)a blockers. To study the incidence of active mycobacterial infections (aMI) in patients starting TNFa blockers, 262 patients were included in this study: 109 with rheumatoid arthritis (RA), 93 with ankylosing spondylitis (AS), 44 with juvenile idiopathic arthritis (JIA) and 16 with psoriatic arthritis (PsA). All patients had indication for anti-TNFa therapy. Epidemiologic and clinical data were evaluated and a simple X-ray and tuberculin skin test (TST) were performed. The control group included 215 healthy individuals. The follow-up was 48 months to identify cases of aMI. TST positivity was higher in patients with AS (37.6%) than in RA (12.8%), PsA (18.8%) and JIA (6.8%) (p < 0.001). In the control group, TST positivity was 32.7%. Nine (3.43%) patients were diagnosed with aMI. The overall incidence rate of aMI was 86.93/100,000 person-years [95% confidence interval (CI) 23.6-217.9] for patients and 35.79/100,000 person-years (95% CI 12.4-69.6) for control group (p < 0.001). All patients who developed aMI had no evidence of LTBI at the baseline evaluation. Patients with CIA starting TNFa blockers and no evidence of LTBI at baseline, particularly with nonreactive TST, may have higher risk of aMI.

Lymphocyte subsets in human immunodeficiency virus-unexposed Brazilian individuals from birth to adulthood

Ethnic origin, genetics, gender and environmental factors have been shown to influence some immunologic indices, so that development of reference values for populations of different backgrounds may be necessary. We have determined the distribution of lymphocyte subsets in healthy Brazilian individuals from birth to adulthood. Lymphocyte subsets were determined using four-colour cytometry in a cross-sectional study of 463 human immunodeficiency virus-unexposed children and adults from birth through 49 years of age. Lymphocyte subsets varied according to age, as previously observed in other studies. However, total CD4⁺ T cell numbers were lower than what was described in the Pediatric AIDS Clinical Trials Group P1009 (PACTG P1009), which assessed an American population of predominantly African and Hispanic backgrounds until the 12-18 year age range, when values were comparable. Naïve percentages and absolute values of CD8⁺ T cells, as assessed by CD45RA expression, were also lower than the PACTG P1009 data for all analysed age ranges. CD38 expression on both CD4⁺ and CD8⁺ T cells was lower than the PACTG P1009 values, with a widening gap between the two studies at older age ranges. Different patterns of cell differentiation seem to occur in different settings and may have characteristic expression within each population.

Undervaccination of perinatally HIV-infected and HIV-exposed uninfected children in Latin America and the Caribbean

BACKGROUND

Perinatally HIV-infected (PHIV) children may be at risk of undervaccination. Vaccination coverage rates among PHIV and HIV-exposed uninfected (HEU) children in Latin America and the Caribbean were compared.

METHODS

All PHIV and HEU children born from 2002 to 2007 who were enrolled in a multisite observational study conducted in Latin America and the Caribbean were included in this analysis. Children were classified as up to date if they had received the recommended number of doses of each vaccine at the appropriate intervals by 12 and 24 months of age. Fisher's exact test was used to analyze the data. Covariates potentially associated with a child's HIV status were considered in multivariable logistic regression modeling.

RESULTS

Of 1156 eligible children, 768 (66.4%) were HEU and 388 (33.6%) were PHIV. HEU children were significantly (P < 0.01) more likely to be up to date by 12 and 24 months of age for all vaccines examined. Statistically significant differences persisted when the analyses were limited to children enrolled before 12 months of age. Controlling for birth weight, sex, primary caregiver education and any use of tobacco, alcohol or illegal drugs during pregnancy did not contribute significantly to the logistic regression models.

CONCLUSIONS

PHIV children were significantly less likely than HEU children to be up to date for their childhood vaccinations at 12 and 24 months of age, even when limited to children enrolled before 12 months of age. Strategies to increase vaccination rates in PHIV are needed.

Pediatric hospital admissions from influenza A (H1N1) in Brazil: effects of the 2010 vaccination campaign

lIn 2009, the influenza A (H1N1) virus spread rapidly around the world, causing the first pandemic of the 21st Century. In 2010, there was a vaccination campaign against this new virus subtype to reduce the morbidity and mortality of the disease in some countries, including Brazil. Herein, we describe the clinical and epidemiological characteristics of patients under 19 years of age who were hospitalized with confirmed influenza A (H1N1) infection in 2009 and 2010. We retrospectively reviewed files from the pediatric patients who were admitted to a university hospital with real-time polymerase chain reaction (RT-PCR) confirmed influenza A (H1N1) infection in 2009 and 2010. There were 37 hospitalized patients with influenza A (H1N1) in 2009 and 2 in 2010. In 2009, many of the hospitalized children had an underlying chronic disease and a lower median age than those not hospitalized. Of the hospitalized patients, 78% had a chronic disease, primarily pneumopathy (48%). The main signs and symptoms of influenza were fever (97%), cough (76%), and dyspnea (59%). Complications occurred in 81% of the patients. The median length of hospitalization was five days; 27% of the patients required intensive care, and two died. In 2010, two patients were hospitalized with influenza A (H1N1): one infant with adenovirus co-infection who had received one previous H1N1 vaccine dose and presented with respiratory sequelae and a 2-month-old infant who had a hospital-acquired infection. An impressive reduction in hospital admissions was observed in 2010 when the vaccination campaign took place in Brazil.

Immune response and tolerability of varicella vaccine in children and adolescents with systemic lupus erythematosus previously exposed to varicella-zoster virus

OBJECTIVES

The aim of the present paper is to evaluate the immune response and tolerability of varicella vaccine in children and adolescents with systemic lupus erythematosus previously exposed to varicella-zoster virus.

METHODS

We performed a prospective and controlled study on a group of 54 SLE patients that were chosen at random to be or not to be vaccinated (28 were vaccinated and 26 were not). Twenty-eight healthy controls, of matching age and sex were also vaccinated. All were submitted to a questionnaire, physical evaluation and laboratory assays: lymphocyte immune-phenotyping by flow cytometry, plasma varicella zoster virus (VZV) serology by ELISA and in vitro interferon gamma (IFNγ) production by T-cells after stimulus with VZV antigen. They were evaluated before vaccination and at 30, 45, 180 and 360 days afterwards.

RESULTS

We did not observe any differences in the frequency of adverse events in both vaccinated groups. At study entry, all individuals were seropositive for VZV antibodies. The serum VZV antibody titres similarly increased after vaccination. The frequency of flares and the SLEDAI score were also similar among the patients. Thirty days after vaccination the production of IFNγ specific to VZV was lower in the SLE group compared to healthy controls. In the follow-up we observed 4 cases of herpes zoster in the SLE unvaccinated group, but no zoster in the vaccinated group.

CONCLUSIONS

The varicella vaccine was well tolerated in SLE group, who had pre-existing immunity to varicella. The varicella vaccine immunogenicity measurement by serum antibody titres was appropriate. The incidence of HZ was lower in the vaccinated lupus group.

Surveillance system of hemodialysis-associated infections in a pediatric unit

The bloodstream infection surveillance system proposed by the Centers for Disease Control and Prevention (CDC) was prospectively conducted in a pediatric hemodialysis unit. Thirty patients were included; 73% had a catheter for vascular access at enrollment. Vascular access infection rate was 21.1 per 100 patient-months, well above those observed in adult patient surveys. Staphylococcus aureus was most frequently isolated (23%).

Interaction between pediatric HIV infection and measles

Infections by measles virus and by HIV cause a state of immunodeficiency in the host. While measles virus leads to a transient immunodeficiency with depression of cellular mediated immunity, natural HIV infection leads to a progressive immunodeficiency of both humoral and cellular immunity. This review will focus on the interaction between HIV and measles virus in pediatric patients. Different scenarios of virus interaction will be dissected and their implications for a practical approach in terms of the individual patient and strategies to eliminate measles virus will be discussed.

Immunization status of residents in pediatrics at the Federal University of São Paulo, Brazil

Vaccination of health care workers is an efficient way to reduce the risk of occupational infection and to prevent nosocomial transmission to vulnerable patients. Despite this, achieving high immunization rates among those professionals is a challenge. We assessed the immunization status of Residents in Pediatrics at the Federal University of São Paulo from June to December 2008. Their immunization records were checked and evaluated according to the Brazilian Immunization Schedule for health care workers. Considering all required vaccines, only 3.1% of the 64 Residents were up-to-date with their immunizations. Influenza was the vaccine with the lowest uptake (3.1%) and measles and rubella were diseases with the highest evidence of immunity (62.5% each). Only 37.5% of Residents had received three hepatitis B vaccine doses with a subsequent serology confirming seroconversion. Moreover, the vast majority of Residents in Pediatrics who were not up-to-date were unaware of the fact. Both medical schools and Pediatric Residence programs should not only offer information but also check vaccination records in an effort to keep their healthcare workers' vaccinations up-to-date.

Low CD4+ T-cell levels and B-cell apoptosis in vertically HIV-exposed noninfected children and adolescents

Lymphocyte subsets, activation markers and apoptosis were assessed in 20 HIV-exposed noninfected (ENI) children born to HIV-infected women who were or not exposed to antiretroviral (ARV) drugs during pregnancy and early infancy. ENI children and adolescents were aged 6-18 years and they were compared to 25 age-matched healthy non-HIV-exposed children and adolescents (Control). ENI individuals presented lower CD4(+) T cells/mm(3) than Control group (control: 1120.3 vs. ENI: 876.3; t-test, p = 0.030). ENI individuals had higher B-cell apoptosis than Control group (Control: 36.6%, ARV exposed: 82.3%, ARV nonexposed: 68.5%; Kruskal-Wallis, p < 0.05), but no statistical difference was noticed between those exposed and not exposed to ARV. Immune activation in CD4(+) T, CD8(+) T and in B cells was comparable in ENI and in Control children and adolescents. Subtle long-term immune alterations might persist among ENI individuals, but the clinical consequences if any are unknown, and these children require continued monitoring.

Immune status and risk perception of acquisition of vaccine preventable diseases among health care workers

Risk perception of acquiring vaccine preventable diseases and the immune status of 187 health care workers (HCW) from a high-complexity university hospital in São Paulo, Brazil, were assessed. The vaccine preventable diseases more cited as at risk for acquisition were hepatitis B (94.1%), influenza (92.5%), meningococcal disease (90.3%), tuberculosis (85.0%), and varicella (72.7%). Previous disease or vaccination reported by HCW were hepatitis B (82.4%), tetanus (87.7%), diphtheria (81.8%), measles (86.6%), mumps (85.6%), rubella (85.0%), varicella (82.9%), and influenza (35.8%). One third of HCW reported previous percutaneous or mucosal occupational accidents, and 83.6% had notified the event to the Hospital Infection Control Committee. Despite good risk perception of acquiring vaccine preventable diseases, only 35.8% of individuals were fully immunized. Efforts should be made to increase influenza vaccination coverage among all professionals and to reduce the number of nonreported accidents, especially among physicians.

Optimization strategy to minimize wastage of palivizumab during the 2008 RSV season in São Paulo, Brazil

Palivizumab is currently recommended to high-risk children as a prophylaxis for respiratory syncytial virus (RSV) infection. However, it is still very expensive for developing countries like Brazil. Herein, we describe our strategy to minimize wastage of Palivizumab during the 2008 RSV season. Appointments were fixed for 304 children on 2 days of the week, so that a mean of 19.9 children received Palivizumab per day. That allowed remaining volumes of Palivizumab vials to be pooled and used for other children on the same day within the 6 h period after opening a vial. That strategy saved 26.3% of vials, which represents USD $749,143.75.

Seroconvertion to hepatitis B vaccine after weight reduction in obese non-responder

Decreased responses to hepatitis B vaccine have been associated with some host conditions including obesity. Susceptible non-responders to a primary three-dose vaccine series should be revaccinated. Those who maintain a non-responder condition after revaccination with three vaccine doses are unlikely to develop protection using more doses. This is a description of an obese woman who received six doses of hepatitis B vaccine and persisted as a non-responder. She was submitted to a vertical banded gastroplasty Roux-en-Y gastric bypass Capellas's technique. After weight reduction, she received three additional doses of vaccine and seroconverted. Further studies should help clarify the need to evaluate antibody levels and eventually revaccinate the increasing population of individuals who undergo weight reduction.

Diphtheria, tetanus, and varicella immunity in health care workers in neonatal units

BACKGROUND

Susceptible health care workers are at risk of acquiring and transmitting vaccine-preventable diseases to or from patients. The objective of this study was to assess antibody levels against diphtheria, tetanus, and varicella in healthcare workers.

METHODS

Antibody levels against diphtheria, tetanus, and varicella were measured in health care professionals in 2 neonatal units at the Federal University of São Paulo, Brazil.

RESULTS

Between September and November 2002, 215 of 222 (96.8%) health care workers were studied. Of those, 122 (56.7%) gave oral information regarding their vaccination status against diphtheria and tetanus and only 9 (4.2%) had their vaccination cards. Geometric mean antibody levels against diphtheria, tetanus, and varicella were 0.89 IU/mL (95%CI, 0.73 to 1.08), 0.86 IU/mL (95%CI, 0.68 to 1.07) and 1.10 IU/mL (95%CI, 0.98 to 1.24), respectively. Using internationally accepted definitions, 200 (93.0%) and 182 (84.7%) individuals had full protection against diphtheria and tetanus, respectively. Regarding varicella, 213 (99.1%) individuals were immune and 2 (0.9%) had equivocal immunity against varicella. Of 65 (30.2%) individuals without previous history of the illness, 63 (96.9%) were immune against varicella zoster virus.

CONCLUSIONS

Based on serologic screening, most professionals were immune to diphtheria, tetanus, and varicella. Absence of previous history of varicella was an unreliable identifier of susceptibility to varicella zoster virus in the health care workers studied.

Prevalence of antibodies against hepatitis A virus among the Kuikuro and Kaiabi Indians of Xingu National Park, Brazil

A seroprevalence study to detect total antibodies against Hepatitis A Virus was done with 220 samples from 589 Native Indians from Xingu National Park, Brazil, in five Kaiabi and Kuikuro villages, the most populous ethnic groups. Using a commercial immunoassay kit we detected 97.7% positive samples (95% Confidence Interval: 95%-99%). We noticed a precocious seroconversion, before the age of six years, when the disease is usually asymptomatic. These results are similar to those found in the literature in non-Indian population studies of the Northern, Northeastern and West Central regions of Brazil. They suggest that it is not necessary to introduce vaccination against Hepatitis A in these highly endemic populations.

Strong HIV-1-specific T cell responses in HIV-1-exposed uninfected infants and neonates revealed after regulatory T cell removal

BACKGROUND

In utero transmission of HIV-1 occurs on average in only 3%-15% of HIV-1-exposed neonates born to mothers not on antiretroviral drug therapy. Thus, despite potential exposure, the majority of infants remain uninfected. Weak HIV-1-specific T-cell responses have been detected in children exposed to HIV-1, and potentially contribute to protection against infection. We, and others, have recently shown that the removal of CD4(+) CD25(+) T-regulatory (Treg) cells can reveal strong HIV-1 specific T-cell responses in some HIV-1 infected adults. Here, we hypothesized that Treg cells could suppress HIV-1-specific immune responses in young children.

METHODOLOGY/PRINCIPAL FINDINGS

We studied two cohorts of children. The first group included HIV-1-exposed-uninfected (EU) as well as unexposed (UNEX) neonates. The second group comprised HIV-1-infected and HIV-1-EU children. We quantified the frequency of Treg cells, T-cell activation, and cell-mediated immune responses. We detected high levels of CD4(+) CD25(+) CD127(-) Treg cells and low levels of CD4(+) and CD8(+) T cell activation in the cord blood of the EU neonates. We observed HIV-1-specific T cell immune responses in all of the children exposed to the virus. These T-cell responses were not seen in the cord blood of control HIV-1 unexposed neonates. Moreover, the depletion of CD4(+) CD25(+) Treg cells from the cord blood of EU newborns strikingly augmented both CD4(+) and CD8(+) HIV-1-specific immune responses.

CONCLUSIONS/SIGNIFICANCE

This study provides new evidence that EU infants can mount strong HIV-1-specific T cell responses, and that in utero CD4(+) CD25(+) T-regulatory cells may be contributing to the lack of vertical transmission by reducing T cell activation.

Anti-hepatitis A virus frequency in adolescents at an outpatient clinic in São Paulo, Brazil

The prevalence of hepatitis A virus (HAV) antibodies was assessed in adolescents (age ranging from 10.4 to 19.9 years) at an Adolescent Outpatient Clinic in São Paulo, Brazil. Anti-HAV was detected in 137 (54.2%) out of 253 individuals. When separated into two age groups, anti-HAV frequency was higher in the 15 to 19 year-old group (64%) in comparison to the 10 to 14 year-old group (46%) (Chi-square test: p = 0.004). These results suggest that adolescents in São Paulo are at risk of hepatitis A infection and are probably contracting HAV infection during this age period.

HIV-1-infected children on HAART: Immunologic features of three different levels of viral suppression

BACKGROUND

HIV-1-infected children show changes of blood lymphocyte subpopulations. We have, therefore, investigated how highly active anti-retroviral therapy (ART) alter these subsets. Blood samples were taken from 41 HIV-1-infected children on ART who were divided into groups showing good, partial and poor responses to ART on the basis of viral load (VL) measurement in blood. The observations were compared to those seen in 20 uninfected children.

METHODS

The samples were studied using 4-color flow cytometry for "naïve", central memory and effector memory cells as well as for CD38 expression as the sign of activation within both the CD4+ and the CD8+ T cell populations. HIV-1 infected children were also evaluated for the presence and the titers of antibodies induced by vaccination against childhood infections in our patients while on HAART.

RESULTS

Lymphocyte counts were lower in the "poor" viral load responding (VLR) group when compared with partial and good VLRs. Poor VLRs had lower total and naïve CD4+ T cell counts. HIV-1-infected children from all three groups had high CD8+ T cell counts. Central memory CD4+ and CD8+ T cell percentages were particularly low in the poor VLR group while in the poor VLR group the percentages of effector memory CD4+ and CD8+ T cells were higher when compared with the control group. Higher cellular activation of CD8+ T cells was observed in HIV-1-infected children, particularly when analyzed for the intensity of CD38 expression in the poor VLR group. CD5 expression on B cells was higher among all HIV-1-infected children. Antibodies to tetanus, diphtheria, measles, rubella, and hepatitis B were present in a large proportion of children but the titers were similarly low for all three groups of HIV-infected children.

CONCLUSIONS

Children with different levels of viral response to HAART present immune phenotype characteristics that tend to place the children with partial and good virological responses into the same group. These children are still moderately deficient in their immune responses but show better recovery than seen with children in the poor VLR group. These observations indicate that the proportions of central memory cells among the CD4+ T cells and the intensity of the expression of CD38 activation antigen on CD8+ T cells provide more informative parameters for monitoring children on HAART than the absolute numbers of CD4+ and CD8+ T cells alone.

Prevalence of IgG varicella zoster virus antibodies in the Kuikuro and Kaiabi indigenous communities in Xingu National Park, Brazil, before varicella vaccination

The purpose of the study was to estimate the prevalence of IgG antibodies against varicella zoster virus (VZV) in the two most populated indigenous ethnic groups from Xingu Indigenous National Park, in Brazil, prior to the introduction of vaccination against the disease, and to determine the positive and the negative predictive values of a history of varicella infection. In 2001, 589 inhabitants of two Kuikuro villages and three Kaiabi villages were evaluated and provided information concerning previous varicella infection. An indirect immunosorbent assay (ELISA) to detect IgG anti-VZV antibodies was performed in 224 blood samples - volunteer selection had no interference of anamnesis. IgG prevalence was 80.8% (95% Confidence Interval: 76% - 86%). The seroepidemiology of varicella in Xingu National Park prior to varicella vaccine introduction was comparable to the Brazilian national seroprevalence described in the literature, and so were the positive (98%) and the negative predictive value (41%) of the referred history.

[The prevalence of hepatitis A antibodies in HIV exposed and/or infected children and adolescents]

OBJECTIVE

To evaluate the prevalence of hepatitis A virus antibodies in HIV-exposed and/or HIV-infected children and adolescents.

METHODS

Between September 1996 and August 2002, 352 patients (200 exposed, but not HIV-infected and 152 HIV exposed and infected) were included in this study. These children and adolescents (age ranged between 1 and 14 years) were all followed up at the Pediatric AIDS Clinic of the Federal University of São Paulo (UNIFESP) and had anti-HAV antibodies determined by a commercially available ELISA method (tests for total anti-HAV antibodies and specific IgM antibodies) (Dia Sorin and Radim). Statistical analyses were done with chi-squared and t test.

RESULTS

The prevalence of hepatitis A virus antibodies in HIV-infected and HIV-exposed, but uninfected patients was 34% and 19.7%, respectively. We noticed that in the age range between 2 years and 10 years, the group of HIV-infected children presented a higher prevalence of hepatitis A virus antibodies (35.5%) than the group of uninfected children (16.7%) (p = 0.005). In the HIV infected group, children from B and C categories had a prevalence of hepatitis A virus antibodies (40.5%) higher than N and A categories (24.1%) (p = 0.042). Mean age did not differ when children from B and C categories were compared with N and A categories (5.18 and 5.66 years, respectively) (p = 0.617).

CONCLUSIONS

The prevalence of hepatitis A virus antibodies in HIV exposed and/or infected children and adolescents between 1 and 14 years old was 26%. Considering the possibility of HIV infection aggravation when associated with hepatitis A virus infection, we suggest that hepatitis A virus inactivated vaccine should be administered to these patients.

A simple and cheaper in house varicella zoster virus antibody indirect ELISA

We have developed a cheaper an simple in house indirect ELISA that uses the live attenuated VZV vaccine as a coating antigen. The alternative ELISA had an agreement of 94% when compared with a commercial VZV ELISA kit. Moreover, our ELISA proved to be more reliable than the kit when assessing true negative samples. By adding a standard serum, we were able to produce results in international units per millilitre. Also, the addition of an extra step with 8M urea allowed the assessment of VZV IgG avidity without excessive costs. The cost per sample to test VZV IgG was 2.7 times cheaper with our ELISA, allowing the testing of many samples without the burden of production of VZV antigen in the laboratory.